still go with bolt action,if your a good shot and know how to move then you can just pick them off,its called concealment and camo.try to find a sniper feild manual.there is a guy who had a bar 10 who can hit a man size target at 300 feet.yes it is moded but just about all the mods.the bolt action is more quiet then a gear box.
You are thinking of MarineSGT, and no offense to MSGT, he's a nut case. His claim is 400 feet with a VSR shooting 825 FPS. Well over our field limits. He does not show any proof that his shots hit 400, just a long frak distance away from the camera.
Falcon's numbers are a bit off, the max effective range of most AEG's is around 150ft, for a well tuned M16 platform, maybe 180-200 feet at 400 FPS. There are those of us who have pushed our effective ranges out furthur than that. My G&G M14 chronos around 390 FPS w/ .25's and has an effective range (60% chance of hitting what I'm aiming at basically) of about 80 yards. I have heavier BB's to test furthur ranges with my M14, but it's a bit of an exception rather than the norm.
In terms of selling a bolt action, it IS a tough sale for our fields. There are very limited places and times of the year in which a bolt action that is highly tuned and has the appropriate FPS could have a range advantage over the hordes of AEG's. Personally, I see FPS over 450 as a disadvantage to the player. The longer MED makes the player useless for engagements that are closer than their MED.
With a well tuned Semi Auto, sniper rifles and "snipers" are absolutely useless on the field. I have made a nasty habit of eliminating snipers with my M14, I know several others who do it with other guns as well, but I really dont see snipers as the threat they are in the real world.